It’s a recent Wednesday night, and the Miami Heat are about to lose to the Chicago Bulls, ending their run of 27 consecutive victories.

Four-fifths of one of Vegas’ best bands, the hard-to-pigeonhole Caravels, take in the game at Rum Runners on Tropicana Avenue. Bassist Cory Van Cleef and singer Mike Roeslein are particularly interested in how the game will affect their fantasy basketball teams.

Playful ribbing ensues, beers are chugged, more beers are ordered. It’s all done with the enthusiasm of an overcaffeinated pep squad.

There’s a loose, easygoing camaraderie about these dudes — some of them have known each other since middle school — and you hear it in their music: No one’s fighting for space, even though everyone is an accomplished player capable of commandeering a tune with well-practiced chops.

Eventually, talk turns to some of the bands they’re most passionate about: Lungfish, Mogwai, Neurosis, Isis, Pelican, among many.

Caravels doesn’t sound like any of those acts, but they do have one thing in common: They’re all feel-based groups who balance enviable levels of musicianship with moments of carefully cultivated atmosphere that makes them difficult to neatly categorize.

“Often, people ask me, ‘What kind of music is your band?’ ” guitarist Matt Frantom says. “And I have no answer.”

He doesn’t need one. Caravels’ recently released full-length debut, “Lacuna,” which just came out on Boston’s Topshelf Records, speaks for itself. It’s a vigorous, often bracing listen, with songs that tend to unfold like a spider spinning its web, slowly, methodically, resulting in an elaborate creation in the end.

Roeslin’s vocals are as brusque and sandblasted as the guitar interplay between Frantom and Dillon Shines is deft and tensile, balancing bombast with nuance.

The album has a distinct ebb and flow, with songs that frequently swell into grandiose new forms. It feels like a culmination for this bunch, which has been around for more than five years now, but which had only released a trio of EPs in the past.

“It’s the first time we’ve had the chance to have 35 minutes to explore what we want to do,” Roeslein says, an idea that drummer George Foskaris elaborates upon.

“There was a grand scope of knowing that it was going to be (a full-length),” he says.

The essence of said scope?

Intensity.

“I feel bad for people in softer bands,” Foskaris smiles, “they must find, like, a totally different zen in playing their instruments.”